At least 22 members of two families were killed in Afghan and US joint operation last week in Sangin district of Helmand province.

Operational authorities of Afghan security forces in Helmand declared that 13 members of one family and 9 members of another family killed in the operation.

The presidential envoy for security in Helmand, Jabar Qahraman said, ” We are saddened to hear the news of civilians being killed. When the Taliban use civilians as their shield against security forces, such incidents occur.”

U.S. Navy Cpt. Bill Salvin, a military spokesman, said “we are working diligently to determine whether civilians were killed or injured as a result of U.S. airstrikes” carried out to support Afghan forces in and around Sangin.

The investigation is “continuing and has not reached any conclusions,” he added in a written statement.

The U.N. mission in Afghanistan expressed “deep concern” at the violence in Helmand, saying its initial inquiries suggest airstrikes by international forces killed at least 18 civilians, “nearly all women and children.”